// https://www.luogu.com.cn/problem/B2064

#include <stdio.h>
#include <string>
#include <iostream>
using namespace std;


int main() {
    string s;
    getline(cin, s);
    int cnt = 0;
    for (char ch: s) {
        if (ch >= '0' && ch <= '9') {
            cnt++;
        } else if (ch >= 'A' && ch <= 'Z') {
            cnt++;
        } else if (ch >= 'a' && ch <= 'z') {
            cnt++;
        }
    }
    printf("%d\n", cnt);
    return 0;
}